Flexible barrier materials for technical applications

Flexible polymeric components with high barrier properties are presently in focus for applications in an increasing number of technical fields. Potential high added-value areas of application are: Improved vacuum isolated panels having lifetimes of decades, encapsulation of solar modules and flexible displays based on organic emitters, possibly in combination with polymer electronic devices. For all these areas, the required oxygen and water vapor barriers are orders of magnitude beyond what can be achieved by current state-of-the-art industrial polymer technology. In order to meet these challenges, complex barrier layer systems are being developed in adapted structures. For display applications, these structures will consist of transparent alternating polymeric and inorganic layers, sequentially applied on top of polymer substrates. The application of economic roll-to-roll processes is a key requirement for any later large scale application. As part of the activities of the Fraunhofer Alliance "Polymer Surfaces", combinations of different inorganic vacuum-deposited coatings and coatings based on inorganic-organic hybrid polymers prepared under atmospheric conditions have been studied. An important feature are the excellent barrier properties of the inorganic-organic hybrid polymers. The barrier properties of those polymeric hybrid layers which are in contact with the inorganic barrier layers represent a scaling factor for the total barrier performance of the layer combinations. These findings have been supported by test productions on a smaller technical scale in roll-to-roll processes.